EP1162096B1 - Filtration device for an apparatus for ventilating and/or heating and/or cooling, especially for a motor vehicle - Google Patents

Description

The present invention relates to a filtration device for equipping a ventilation apparatus and / or heating and / or air conditioning, especially for a motor vehicle.

In a motor vehicle the apparatus inside which the filtering device is mounted comprises at least one inlet part provided with at least one fan. This inlet portion is used to take air from outside, which - downstream of the fan, alternatively upstream of the fan - is intended to pass through the filter device. Downstream of this input part is provided a heating radiator in communication with the interior of the vehicle. Alternatively as visible in the document EP-A-0 634 299 an air conditioning device is provided with an evaporator placed downstream of the filtration device. In this configuration the input part of the aforementioned apparatus is also used to take air from inside the vehicle.

The filtration device thus makes it possible to filter the polluted air coming from outside and / or from inside the vehicle. This device comprises at least one frame and a filter media.

It has already been proposed in the documents GB-A-1,182,595 (disclosing all the features of the preamble of claim 1), DE-A-28 25 171 and FR-A-2,794,405 (Not published on the priority date of the present application) to provide such a filtering device with an odorization function. More precisely in the document GB-A-1,182,595 there are provided pockets carrying an adsorption media treated with perfume and / or a disinfectant so that the life of such an odorizing device is not as long as desired the perfume being released during storage of the filter. In the document FR-A-2,749,405 an extract of liquid perfume or essential oil is sprayed onto the filter so that the odorizing device is released immediately after spraying.

In the document DE-A-28 25 171 there is provided an odorizing device in the form of needles filled with deodorant and pressed into the filter media of the filtration device. It is possible to replace the needles.

This provision is not applicable when the filter media is thin, especially when it is pleated type. In addition, needles can be lost during handling, packaging or transport of the filtration device.

The object of the present invention is to provide, in a simple and economical manner, such a filtration device with a thin filtering medium of an odorization function.

Thus, according to the invention, a filtration device intended to equip a ventilation and / or heating and / or air conditioning apparatus, in particular for a motor vehicle, of the type comprising at least one frame, a filter media, in particular pleated type, and an odorizing device, is characterized in that the odorizing device consists of odorization microcapsules associated with the frame and / or the filter media.

Advantageously, the filtration device also comprising at least one grid; according to the invention, the odorization microcapsules are associated with the grid.

All combinations are possible.

The microcapsules contain in one embodiment of the perfume, alternatively the microcapsules contain an essential oil. Alternatively the microcapsules also contain a disinfectant such as an anti-bacterial. As a variant, disinfectant microcapsules are added to the deodorant microcapsules.

During the use of the filtration device the membranes, usually plastic, microcapsules are eroded either by air or by particles of air, which gradually releases the odorous material thereof for example perfume.

A pleasant smell is thus generated in the passenger compartment of the motor vehicle throughout the life of the filter media.

Thus, thanks to the presence of membranes, the odorization function has a longer life than if we dipped the filtration device or at least one of the components thereof in a bath filled with an odoriferous material.

In addition, the amount of odorous material used is smaller thanks to the microcapsules, which by definition have a small size, allowing passage of the air, in particular through the filter medium.

These microcapsules are associated, that is to say linked by any known means, to at least one of the components of the filtration device so that the filter media can be in all cases of the pleated type.

In any case before use of the filtration device, for example during handling, transport and / or conditioning of the filter medium, unlike the needles of the prior art, there is no risk of losing the microcapsules so that the solution is reliable.

Preferably, the filter media comprises a nonwoven mat consisting of a card web.

In one embodiment, said nonwoven mat consisting of a card web is applied against said grid without being secured to it. In a variant, the card web is secured to the grid.

Preferably, said card web forms a single web.

Advantageously, said card web is placed upstream of the grid by considering the normal direction of passage of the gas to be filtered.

Preferably, the filtration device comprises gas adsorption means placed between the grid and said nonwoven mat.

Advantageously, said adsorption means comprise an activated carbon fabric.

Advantageously, said adsorption means comprise an activated carbon bed.

Preferably, a nonwoven mat consisting of a card web is disposed on either side of the adsorption means.

Advantageously, a second gate, called gate entry, is arranged upstream of the nonwoven mat.

Preferably, the two grids are of the same kind and are in one embodiment secured to the filter media.

Preferably, the nonwoven mat is based on long fibers, the length of which is preferably at least 38 mm.

Advantageously, said long fibers have a mean diameter of at least 1 μm.

Preferably, said long fibers are made of thermoplastic material.

Advantageously, said long fibers are polypropylene fibers.

Advantageously, the grid is made of polypropylene.

Preferably, the frame is made of polypropylene.

Advantageously, the microcapsules are deposited by any known means, for example by spraying, on the surface of the filter media and / or the frame and / or the grid.

Alternatively, the microcapsules are introduced into the mass of material (s) from which are made the filter medium and / or the grid and / or frame.

More specifically, the filtering device comprises a preferably pleated flexible grid against which is arranged, without being secured to it, a filtering media forming a particle filter, formed of a mat of nonwoven consisting of a card web in a single layer. . The filter media is itself pleated in the same way as the grid. Alternatively the grid is secured to the filter media for example by ultrasonic welding. Thus, in a first step, the filtering medium is superposed in a sheet and at least one grid made of thermoplastic material, then, in a second step, the grid and the filter medium are fixed by means of ultrasonic welding, and finally a step of pleating of these two superimposed elements. The welding step is in one embodiment carried out using a sonotrode on the same machine as the pleating step. Alternatively the fixing step consists of a hot calendering of these elements arranged between rollers or calender over their entire surface. No uncoupling can thus occur in the event of shocks, falls or vibration during handling, packaging or transport.

Said nonwoven mat is based on long fibers whose length is preferably at least equal to 38 mm. Said long fibers have a mean diameter of at least 1 μm. Said fibers are made of thermoplastic material and, here, of polypropylene.

The grid is made of thermoplastic material, here in polypropylene. It is placed downstream relative to the direction of air flow in the filtration device.

A second pleated and flexible grid may be provided so that the filter medium is placed between the grids without being secured to either of the two grids. In a variant, the filter medium is secured to the two grids in the aforementioned manner, for example by ultrasonic welding.

Preferably, the so-called second inlet gate is placed upstream of the media in the direction of air flow in the filtration device.

Advantageously, the second grid is of the same nature as the first flexible grid and is here made of polypropylene.

In a variant, the two grids are of different natures.

The filtration device constitutes a particulate filter.

The invention also relates to a so-called combined filter, that is to say both a particulate filter and a filter stopping deleterious gases.

In this case, to the basic structure consisting of the downstream gate and the media, are added gas adsorption means placed between the gate and the media so as to have successively, in the direction of air flow , the media, the gas adsorption means and the downstream gate.

A combined filter advantageously comprises, successively, in the direction of air flow, an inlet gate, a media, gas adsorption means, a media and an output gate. The media are advantageously of the same nature as that described above. In this way, two mats of nonwoven each consisting of a card web are disposed respectively on either side of the gas adsorption means.

Said gas adsorption means may comprise an activated carbon bed, but preferably they comprise a carbon fabric pleated in the same manner as the grid and the media.

When the filtration device has a symmetrical construction, it advantageously allows its mounting indifferently in one direction or the other in a heater and / or ventilation and / or air conditioning, which makes it unnecessary to provide, in this case , a key for the mounting direction. The filtration device is thus reversible. Of course, in this case, the input gate can act as an output gate and, conversely, the output gate play the role of gate entry.

A frame is provided to support the various components of the filtration device.

The frame is made for example of thermoplastic material, here polypropylene, and is secured to the output grid or the input gate, and preferably to both grids when both are provided.

The joining of a grid to the frame is advantageously effected by a so-called mirror welding operation which consists of heating simultaneously until the beginning of fusion a peripheral part of the grid, on the one hand, and a portion of the frame corresponding to the fixing zone, on the other hand, then to bring closer and tighten against each other this peripheral portion and this portion so as to exert a relative pressure.

The mirror welding operation is conducted in such a way that the lateral end of the grating is caused to bend at a right angle to fit the corresponding inner face of the frame, which has the advantage of ensuring better fixing of the grating. and to avoid any air leakage between grid and frame.

Advantageously, several peripheral parts and corresponding portions of the grid and the frame are thus fixed together.

The same chemical nature, here polypropylene, grid and frame allows a strong and durable fixation.

During the mirror-welding operation, the non-woven mat or mats are affixed against the corresponding grid or grids with, if appropriate, interposed in the manner previously described, adsorption means such as, preferably, a fabric of carbon.

Alternatively, the frame is molded around the grid or two grids and on the filter media or.

A preferred method of manufacturing a filtration device is as follows.

Polypropylene fibers having a fineness of 1.7 dtex (diameter 14 μm) cut to a length of 40 mm are introduced into a mixer.

The obtained fiber mixture is then introduced into a demoteuse and then into a storage silo before being carded by means of a wool double-dobby type card equipped with a jammer type jumble to obtain a veil isotropic card.

The web is, at the card outlet, introduced into a condenser to form a web.

The parameters of the card and the condenser are chosen so as to obtain a sheet having a basis weight of about 20 to 150 g / m ² .

The sheet is deposited on a carpet and consolidated by a hydraulic binding operation.

The hydraulic bonding operation is to pass through the web disposed on a rotating drum by very fine water jets under high pressure, between 40 and 200 bar.

By bouncing on the drum, the jets of water cause a knotting of the fibers giving the web a significant mechanical strength without significantly increasing the density.

After passing through a drying tunnel, the sheet is rolled up.

The web is then resumed to undergo a pleating operation and is then ready to be mounted on a support to form the filtration device as previously indicated.

The filtration device comprises a sheet in a single layer; in this way, with a sheet of 0.84 mm thick, it was possible to form a filter having a basis weight of 66 g / m ² and density 0.07.

To test the effectiveness of the filter thus produced, the latter was placed across a vein of section equal to 100 cm ² , traversed by a stream of air loaded with particles at a speed of 20 cm / s.

The particles correspond to a powder called "fine SAE powder" which is defined by the standard of the United States of America, reference SAE J 726 / ISO 5011.

The particle concentration is 100 mg / m ³ .

On the one hand, it can be seen that the pressure drop across the filter is, under these conditions, only 14 Pa and that, on the other hand, the efficiency reaches 80%.

Compared to the filtration devices currently on the market, we obtained an efficiency comparable to the best of them with a product with a much lower density (0.07 against 0.12 to 0.30) and causing a loss. much lower charge.

Endurance tests have also demonstrated greater stability over time of the efficiency of the filtration device.

To equip such a filtering device with an odorization function, microcapsules containing an odorant, here a perfume, are deposited on the surface of the fibers of the filter media here after the passage of the sheet in the drying tunnel. This arrangement combines well with the aforementioned filter low thickness and low pressure drop.

During the use of the filter, the membranes of the microcapsules are eroded and the perfume is released gradually; a pleasant smell is generated. Thanks to the invention, the odorization is obtained without the need to add an odorant, in the form of wafer or other, in the room or the cabin.

Alternatively the microcapsules are deposited on the surface of the frame and / or the grid.

The invention also provides for the introduction of microcapsules into the mass of material (s) from which the fibers of the filter medium and / or the grid and / or the frame are made.

For example, in an easy manner, the microcapsules are deposited on the frame or the microcapsules are introduced as part of the document. EP-A-0 634 299 at the central opening thereof facing the filter media and / or at the bypass openings thereof.

When the microcapsules are introduced into the frame or deposited on the frame, the pressure drops are minimized since the filter medium is not affected by the microcapsules.

When the microcapsules are associated with the frame and the filter media, the filter media is totally affected by the microcapsules or alternatively partially for example in the vicinity of the frame to reduce the pressure drops.

The combination of micro-capsules with the grid is easy to achieve because this grid has spaced apart bars extending longitudinally and / or vertically with respect to the filter medium so that one can choose the bars that will be associated with the micro-capsules. capsules. The location of the microcapsules is therefore more precise and easier to achieve than on the filter media. Of course, the second alternative grid carries scented microcapsules.

In the foregoing, the filter media comprises a nonwoven mat but, as is readily understood, the invention applies regardless of the type of filter media which may comprise, for example, a bonded web of a card hydraulic associated with said mat; alternatively, it is a fibrous complex comprising two layers of nonwoven between which is disposed a reinforcing grid, the assembly being secured by interpenetration of the two layers of nonwoven.

Similarly, with regard to the frame, it may be a total or partial frame made by gluing, welding, overmolding or other, removable or not.

Claims (21)

1. Filtering device designed to equip a ventilation and/or heating and/or air-conditioning system, in particular for a motor vehicle, of the type comprising at least a frame, a filtering medium, in particular of the folded type, and a fragrance device, characterised in that the fragrance device consists of micro-capsules associated with the frame and/or the filtering medium.
2. Filtering device designed to equip a ventilation and/or heating and/or air-conditioning system, in particular for a motor vehicle, of the type comprising at least a frame, a filtering medium, in particular of the folded type, a fragrance device and at least one grid, characterised in that the fragrance device consists of micro-capsules associated with the grid.
3. Filtering device according to claim 1 or claim 2, characterised in that the micro-capsules contain a perfume and optionally a disinfectant, and in that the micro-capsules are associated with the frame and/or with the filtering medium and/or with the grid.
4. Filtering device according to one of claims 1 to 3, characterised in that the filtering medium comprises a mat of non-woven fabric consisting of a web which is applied against the grid and is rendered integral with it.
5. Filtering device according to one of claims 1 to 3, characterised in that the filtering medium comprises a mat of non-woven fabric consisting of a web which is applied against the said grid without being rendered integral with it.
6. Filtering device according to one of claims 4 or 5, characterised in that the said web forms a single sheet.
7. Filtering device according to one of claims 2 to 6, characterised in that the said web is placed upstream from the grid, considering the normal direction of passage of the gas to be filtered.
8. Filtering device according to one of claims 2 to 7, characterised in that it comprises means for absorption of gas placed between the grid and the said non-woven mat.
9. Filtering device according to claim 8, characterised in that the said adsorption means comprise an active carbon fabric.
10. Filtering device according to claim 8, characterised in that the said adsorption means comprise an active carbon bed.
11. Filtering device according to one of claims 8 to 10, characterised in that a mat of non-woven fabric constituted by a web is disposed on both sides of the adsorption means.
12. Filtering device according to one of claims 2 to 11 taken in combination with claim 2, characterised in that a second grid, known as the intake grid, is disposed upstream from the mat of non-woven fabric.
13. Filtering device according to claim 12, characterised in that the two grids are of the same type.
14. Filtering device according to one of claims 4 to 13, characterised in that the mat of non-woven fabric is based on long fibres, the length of which is preferably at least equal to 38 mm.
15. Filtering device according to claim 14, characterised in that the said long fibres have an average diameter at least equal to 1µm.
16. Filtering device according to one of claims 14 or 15, characterised in that the said long fibres are made of thermoplastic material.
17. Filtering device according to one of claims 14 to 16, characterised in that the said long fibres are polypropylene fibres.
18. Filtering device according to one of claims 2 to 17, characterised in that the grid is made of polypropylene.
19. Filtering device according to one of claims 1 to 18, characterised in that the frame is made of polypropylene.
20. Filtering device according to one of claims 2 to 19, characterised in that the micro-capsules are deposited on the surface of the filtering medium and/or the frame and/or the grid.
21. Filtering device according to one of claims 2 to 19, characterised in that the micro-capsules are introduced into the mass of material(s) from which the filtering medium and/or the grid and/or the frame are made.